Behavioral search drivers allow more information about the behavior of individuals in an environment to be used during selection. In this paper, we examine several selection methods based on de-aggregating the motion of soft robots into behavior vectors used to drive search. We adapt three behavioral search drivers to this task: є-lexicase selection, discovery of objectives by clustering, and novelty search. These methods are compared to age-fitness pareto optimization and random search. We analyze how these search drivers affect the diversity and quality of soft robots that are tasked with moving as far of a distance as possible. Perhaps the most surprising finding is that random search with elitism is competitive with previously published methods. Overall, we find that elitism plays an important role in the ability to find high fitness solutions, and that lexicase selection and discovery of objectives by clustering with elitism tend to produce the most fit solutions.

A common idiom in biology education states, Eyes in the front, the animal hunts. Eyes on the side, the animal hides. In this paper, we explore one possible explanation for why predators tend to have forward-facing, high-acuity visual sys- tems. We do so using an agent-based computational model of evolution, where predators and prey interact and adapt their behavior and morphology to one another over successive generations of evolution. In this model, we observe a coevolutionary cycle between prey swarming behavior and the predators visual system, where the predator and prey continually adapt their visual system and behavior, respectively, over evolutionary time in reaction to one another due to the well-known predator confusion effect. Furthermore, we provide evidence that the predator visual system is what drives this coevolutionary cycle, and suggest that the cycle could be closed if the predator evolves a hybrid visual system capable of narrow, high-acuity vision for tracking prey as well as broad, coarse vision for prey discovery. Thus, the conflicting demands imposed on a predators visual system by the predator confusion effect could have led to the evolution of complex eyes in many predators.